Volver
by EvilRegalOncer
Summary: "The world stops as Alex's eyes zoom over the page. Her grip gets tighter and tighter, vision blurring until the words swim together. Alex's knees buckle and she sinks to the floor, because this can't be true. It can't be. Kara can't be gone, vanished into some unknown corner of the world without her." Alex finding Kara's letter and the aftermath. Sequel to "Rise".
1. Chapter 1

**AN: Not mine.**

* * *

Alex has no idea what time it is when she finally stumbles through her front door. She's been at the DEO for nearly thirty-six hours straight, trying desperately to protect J'onn, but finally she couldn't hide her fatigue and exhaustion anymore. After everything that's happened, it's a miracle she made it as long as she did, but finally J'onn told her to go home. He's always been able to tell when she's at her limit.

 _"They're not going to do anything for the next few days. Go home and get some sleep, Agent Danvers."_

 _"J'onn—"_

 _"That's an order."_

Even though he's no longer her boss, it still felt wrong to refuse. So after pressing her hand to the glass one more time, Alex left. Thank god she's had a lot of practice driving dead tired, because otherwise they'd probably be peeling her off the pavement.

Astra is nowhere to be found as Alex enters the dark apartment, but Alex doesn't think much of it. She's probably asleep, the effects of the Kryptonite sword not completely gone yet. Rubbing gritty eyes, Alex chucks her keys on the table. Time for a nice big glass of wine (she hasn't slept without some….help….for a while now) and then sleep.

 _Thunk._

Alex blinks in surprise. At first the sound doesn't register, and her sleep-deprived brain fumbles to come up with a source. Keys. She threw her keys on the table. But there was no metallic clinking noise. The hell?

She turns to look, and her gaze falls upon the keys, which are sitting on top of an envelope. It doesn't look like mail; there's no stamp or return address, and the only person who could have brought it in is Astra, who she's almost positive doesn't even know what a mailbox is. Alex moves closer and picks up the envelope, and her heart crawls into her throat as she sees her name written on it.

That's Kara's writing.

Alex's heartbeat thuds in her ears, and she almost rips the envelope in half in her haste to get it open. Tears are already burning her eyes.

 _Alex,_

 _I don't know what to say to you. I don't know how to express how sorry I am. What I said….I'd be lying if I said it wasn't true. We both know that. But I never meant to hurt you. I never, ever wanted that. You have always been there for me, always been my strength even when I didn't deserve you. And I threw it all back in your face. I can't ever forgive myself for that._

 _By the time you get this, I'll be far, far away. I want to make sure I can't ever hurt anyone ever again. Least of all you. When I became Supergirl, I didn't do it just for National City. I did it for you. You've spent your whole life protecting me; I wanted to protect you, Alex. My sister. My friend. My everything. But I failed. I failed so completely that I don't think it can be fixed._

 _I love you, Alex. I love you so, so much. I can never thank you for everything you've done, everything you've been, for me. My life on Earth would have been so horrible without you—actually, I think I might have turned into a monster without you. I might have joined Aunt Astra and Non. You taught me to be human. You showed me how not to be afraid. You promised me I would never be alone. And you never stopped believing, even though I don't deserve it anymore. From the bottom of my heart, Alex, thank you. Thank you, thank you, thank you._

 _I told you that you had no life without me. Well, that doesn't have to be true anymore. Go. Find yourself, Alex. Find who you are, not who I needed you to be. I think you can do it. Hell, I know you can. You might even be surprised at what you find. I wish I could be there to see it, but I know as clearly as I've ever known anything that this is for the best. Just promise me you'll be happy._

 _You will always be in my heart. I love you, Alex._

 _—Kara_

The world stops as Alex's eyes zoom over the page. Her grip gets tighter and tighter, vision blurring until the words swim together. Alex's knees buckle and she sinks to the floor, because this can't be true. It can't be. Kara can't be gone, vanished into some unknown corner of the world without her.

If J'onn were still in charge, Alex could hightail it back to the DEO; could use every technology known to man to find her sister and bring her home. But she can't. J'onn is as good as dead; they both know it, even if the words never passed between them.

She can't have lost her little sister.

But she has. And now…. Kara is never coming back.

Alex is utterly alone.

Something builds inside of her, something deep and ugly and primal. It tears at her throat with razor claws, punches out her chest and makes her bleed. Alex crumples the letter in her hands and screams, shattered, stripped of everything that's ever mattered to her, every reason she ever had for fighting. She screams and screams, her heart somehow still beating even though surely she must be dead, surely this must be hell, because Alex can't even fathom a world without Kara.

Someone's arms wrap around her, pull her close. She smells earth and wind and leather, knows in some tiny, still sane part of her mind that this person is important, but it doesn't matter. Nothing matters anymore. Alex lets out a horrible cry, struggling in vain against the powerful grip, needing not comfort but to bleed the world and watch it burn, because her world has crumbled into less than dust. "LET ME GO!" she screams, claws and writhes, fists and elbows flying. There is no technique at all, none of the skills she's used every day for what feels like her entire life. Only rage is left; rage and a deep, deep, unspeakable grief. Everything that Alex was is dead, dead as Krypton. Now….she's less than nothing, more animal than human. "LET ME GO!"

 _"ALEX!"_

Time stops. The vortex of rage and grief and pain simply melts away, as if it had never been there in the first place. Alex turns wild eyes to the one who spoke, her heart fit to burst from her chest. It can't be. It _can't_ be. Her family is gone….. _she's_ gone, forever…

But it is. Her baby sister is standing in front of her, eyes wide in horror and remorse, tears pouring down her cheeks. Alex goes utterly still, a tiny, tiny whimper slipping from her lips. Her heartbeat crashes in her ears, drowns out everything else. The arms around her loosen, and she all but leaps, catching the blonde in a crushing embrace and burying her face into a blessedly familiar shoulder.

"Kara," Alex sobs, rough and ragged from screaming. "Kara, Kara, Kara….." She trembles, utterly overcome, reduced to nothing but blessed relief. "Kara…."

It's too much to bear. Everything comes crashing down on her with the force of a runaway semi, and Alex collapses into unconsciousness.


	2. Chapter 2

**AN: Not mine.**

* * *

Sunlight stabs her in the eyeballs when she wakes.

Alex groans and rolls over, burying her head into her pillow. She's so tired. J'onn all but kicked her out of the DEO, so surely there's no harm in staying here just a little while longer…

J'onn. Kara. Red kryptonite. The letter!

She sits bolt upright, heart clenching in her chest. "Kara?! KARA!"

"Hush, brave one." Astra's voice washes over her like a soothing balm as a gentle hand cups her face. "Kara is here. She is safe. I convinced her to leave you just long enough to assuage her fears about the state of the Green Martian. She will return soon."

Alex sucks in a shaky breath and closes her eyes, briefly overwhelmed. "I guess we don't have to worry about her finding out about you anymore," she manages at last.

"I saw her leave the letter on your table and thought the best course of action was revealing myself." There's a slight hesitation in Astra's voice, as though she's not telling Alex something important, but Alex honestly isn't sure if she can handle anything else at this point, so she doesn't ask. "Upon seeing your reaction, it seems I was correct." Astra softens, thumb stroking across Alex's cheek and brushing away the droplets of moisture she finds there. "You frightened me, brave one."

"Blame it on your niece. She's so fucking _stupid_." Alex's voice cracks. "In what world does running away make any kind of sense at all?"

"She was under the impression it was for your protection." Astra shifts so that she's sitting next to Alex, dropping her hand from the human woman's face and wrapping an arm around her. "Kara is nothing if not noble."

"Fucking idiot is what she is. Doesn't she know I need her?" She turns her face against Astra's shoulder.

"She knows she caused pain to the one she loves most of all. And that tears her apart." Astra lowers her head until her lips are brushing the top of Alex's head.

"She was right, you know. Not about…..you, but everything else…" A vise grips her heart with steely pincers. "She's been my life since I was fourteen. And I love her dearly, but…. I do resent her. Somewhere inside…..and she knows." Alex's voice quivers. "I love her so much, Astra, how could I ever resent her?"

"Your mother placed a heavy burden on you. One that, perhaps, you were unwilling to bear. No, Alexandra," Astra cuts Alex off as the human starts to protest, "that is not a crime. Your world was changed forever when Kara came, and you were given more responsibility than any child should have to bear. I know that now it is a weight you carry gladly because you love her, but the fact remains. She was your responsibility before she was your sister."

"I love her," Alex cries, half-pleading and half-defensive.

"I know, brave one." Astra pulls her closer as she lifts her hand to protectively cradle the back of Alex's head. "I know you do."

"I don't want to lose her….she's family…."

"You will not lose her. I swear it. Now rest, my Alexandra." Astra presses her lips to the top of Alex's head as she leans back against the pillow, Alex still tucked firmly against her. "You humans need your sleep."

Alex is too drained to argue.

* * *

"Aunt Astra?" Kara slowly pushes the door open, keeping her voice low to avoid waking her sister.

"Hello, little one. Is the Martian all right?" Astra could care less whether he lives or dies, but he clearly means a great deal to both Kara and Alex.

"For now." Kara bites her lip, and if Alex weren't clinging so tightly to her, Astra would move to her little one's side and soothe her fears away. "He was being hunted before Alex's dad died to save him, so I'm not sure if they're still going to…"

"He knew what he was doing. He made his choice, both to protect Alexandra and keep you from doing something you could never forgive yourself for." Absently she pushes Alex's hair back out of her face. "He is noble and brave."

Kara pauses, her eyes falling to her sister draped over her aunt. "Uh…."

Astra actually flushes. "She woke before you returned and was….distressed, and so I….we have become closer since the start of our deception, naturally, but this is not…."

"Oh, gross," Kara groans, "you so have a thing for my sister!"

"I have a—thing? That is terribly unspecific."

"Like…you like her. You want to date her."

"Date? How do you date a person?" Astra knits her brow. "She has not told me her day of birth, true, but what does that have to do with anything?"

In spite of everything, Kara can't hold back a tiny smile. "Aunt Astra, on earth, we call courting 'dating'."

It's amazing how red Astra turns.

"Would you two shut up?" Alex slurs, eyes still closed. "'m trying to sleep."

Kara swallows hard, but then her sister opens her eyes and looks right at her and reaches out. "C'mere. You should sleep too."

"Alex…" she starts, shaking her head, but Alex just rolls her eyes.

"Look, we can talk about this later when I don't feel like I haven't slept for a year. You can bet your ass I'm pissed as fuck and I'm going to kick the crap out of you in the kryptonite training room first chance we get, but for now…" She softens. "Please."

Astra shifts out from underneath Alex to give the two some privacy, unable to resist kissing the top of Alex's head again and smiling slightly at the grateful look she receives. The general—former general, now—wraps Kara in a brief yet fierce hug, pressing a kiss to her niece's forehead before leaving the room. Kara swallows again and slowly moves over to the bed, and Alex scoots back to give her some room, lifting the covers like they're children again. Kara pauses just long enough to take her glasses off and put them on Alex's nightstand before slipping under the sheets and curling close. Alex wraps her sister in a hug that would have been painful if Kara were human. "I love you, idiot," she whispers. Kara presses her face into Alex's shoulder, unable to hold back tears.

"I love you too. I'm so sorry—"

"I know. It's going to be okay. Just rest now," Alex soothes. Kara closes her eyes, letting Alex's heartbeat calm her the way it always has, and soon she's asleep.

Alex stays awake for a while longer, guilt churning in her gut, but eventually her own exhaustion wins out and she's asleep too.

Tomorrow, when they wake, there will be bridges to mend and painful truths to unearth. There will be tears and guilt, but the important thing is that they're together.

Just like always.


	3. Chapter 3

**AN: Not mine.**

 **When I wrote this, I hadn't seen the new episode, so I took a few liberties with the Alex/J'onn flashback scene.**

* * *

Alex keeps still when she wakes, although it's useless. Kara will be able to hear the change in her heartbeat and breathing that signify a return to consciousness. But she's not ready to dredge up what happened, to admit that Kara was right. God, just the thought makes her feel sick. How can she face her little sister and admit that somewhere, deep down in a place she's tried to deny for twelve years, she resents the person she loves the most? How can she face that without Kara, she doesn't even exist?

"Less thinking, more hugs." Kara's voice is still thick with sleep as she curls closer to Alex. Alex can guess that she probably doesn't want to face the day either, especially after seeing her sister's anguish the night before. "I can hear you thinking."

"There's a lot to think about," Alex says softly. She lifts a hand and curls her fingers into Kara's hair, cradling the blonde's head to her shoulder and nestling her cheek on top of golden hair. Her heart hammers in her chest, dread coiling in her belly. "For both of us."

"I don't want to talk about it." Kara's whisper is tiny, and Alex's heart aches at the sound. Kara's words under the red Kryptonite had hurt deeply, but her remorse and guilt now are even worse. Alex wishes she could take Kara's pain even though she's fairly sure the combined weight of that and what she's already feeling would crush her. But then, since when has she cared about her own wellbeing when Kara's is in jeopardy?

"We need to, Kara. This isn't healthy for either of us. We both have things that have festered...things we need to say." Alex takes a breath. She would rather eat rusty nails than have this discussion. "But first...we need to talk about the letter."

Kara sits up and swings her legs over the side of the bed. She doesn't get up, much to Alex's relief, but it's painful to see how rigid the lines of her body are. "I can't risk that happening again. Next time, there might not be a magic gun to stop me. You know what I can do, Alex..." She chokes back a sob, her hands fisting on her knees. "I don't ever want to hurt anyone again. I thought if I-" She abruptly cuts off. "I wanted to make sure I couldn't."

"Astra wasn't telling me something." Alex's stomach is churning; she hopes in vain that she's wrong. "Something about you leaving the letter here. What was it?"

"Please don't ask me that," Kara whispers, voice shaking.

"Kara," Alex insists, although she feels like she's about to vomit. "Tell me."

Kara's silence is all the confirmation she needs.

Alex hunches over, her head between her knees as she fights the urge to be violently sick. Tears roll down her face, and she can't help but wonder how she could have let Kara down so badly. "I'm-"

"Alex, no." Kara's arms wrap around her, her chin settling on the brunette's hair. "It wasn't your fault. It was me. I hurt you; I let everyone down. It doesn't matter that my brain was altered. In the end...the red Kryptonite just brought out the worst in me. It was still me." She sniffles. "You're not to blame."

"I should have protected you." Alex squeezes her eyes shut.

"Alex, you couldn't have known! Nobody knew that stuff was up on the roof, and even if we had, it was anyone's guess as to what would happen. Kal called when I was on my way to see J'onn, and he said that no two bits of red Kryptonite are alike. The effects are always different." Kara kisses her hair. "Please, don't blame yourself. You always blame yourself for me."

"You wanted to-" Alex's voice breaks. "I could have lost you. I can't lose my sister..." She wraps her arms around Kara, burying her face into the blonde's shoulder. "I can't..." Losing Kara to the Black Mercy was horrifying, fearing her loss after revealing her part in Astra's (faked) death even more so, but after the whole red Kryptonite episode and reading the letter on top of it...well, it's doubtful she's ever going to sleep again without alcohol. Copious amounts of it.

"I'm here. I'm here." Kara presses her forehead to Alex's hair. "I'm right here. I'm so sorry I hurt you..."

"I can't live without you," Alex whispers after a long silence. "If it hadn't been for Astra last night...I wouldn't be here right now." A violent shudder rips through her as she remembers her reaction, remembers what she was reduced to in a world where her sister didn't exist.

Kara lets out a strangled whimper and tightens her grip so much that it hurts, but Alex could care less. She holds Kara as close as she can, tears streaming down her cheeks. "I love you, Kara. I love you so fucking much."

She doesn't want to keep going, doesn't want to admit her own dark secret, but if she doesn't, nothing will ever be fixed. Alex pulls away from her sister, curling in on herself with shame. "But you were right. Somewhere inside...I resent you. And it's not fair, it's not fair because you're my sister and I would die for you..." Alex sobs convulsively.

Tears gleam on Kara's cheeks, but her voice is steady when she answers. "I would have resented me too if I were you. You said it yourself. You were the star. And suddenly, I could touch them. Alex, I've always felt horrible about how Eliza treated you. Treated /us/. She made you responsible for me, and you shouldn't have had to be. You're not accountable for my actions. You don't have to suffer for me, Alex. That's not what I want. I would rather have Lane inject me with Kryptonite than cause you pain."

"Did you really believe I hated you?" Alex lifts her head, needing to see Kara's face. Whatever the answer is, she needs to know.

Kara swipes at her eyes, shaking her head. "No. No, I didn't. Just because I thought it doesn't mean I believed it."

Alex sobs again, this time in relief, and puts her head back down. Kara's voice breaks the silence a moment later. "Alex, I...you've smelled like alcohol for a while now, but I didn't say anything because...well, I was afraid of what you'd tell me. I guess now I know why. Are you...have you started drinking again?"

Fuck. Her shoulders tense. "That's not your-"

"Alex," Kara begs. "Last time, you-you-"

"Yeah, I remember." Waking up in a jail cell once was more than enough; she's not keen to repeat the experience, even if she did end up getting a job out of it.

"You almost died," Kara whispers, and fuck if her voice doesn't cut like a knife. Or a sword, Alex thinks, remembering how she so easily sheathed that Kryptonite blade in Astra's back.

"I'm okay, Kara." She raises her head slightly, offering her sister a thin smile. "At this point, my liver is used to abuse."

That's the wrong thing to say, because less than a heartbeat later Kara's arms are around her with enough strength to make her bones creak dangerously. "Kara, ow!" Alex yelps, struggling uselessly.

"I'm sorry!" The embrace loosens, but not enough to let Alex pull away. "I just...why don't you take better care of yourself? Don't you know that you matter to me?" The hurt and pained confusion in Kara's voice cuts Alex to the core, and despondently she wonders if a day will ever come where she doesn't cause her sister some kind of distress.

"I don't matter, Kara. You said it yourself: I have no life outside of you. Maybe...maybe I'm not meant to. If I'm here just to protect you...well, I guess I can live with that." Even as Alex speaks, her chest aches, but she pushes it aside. Kara is the most important thing; will always be the most important. Her own life means nothing in comparison, a lesson she's had drilled into her since the age of fourteen.

"I can't!" Kara cries. "I want you to be happy, Alex. You deserve to be happy. Why can't you see that?"

"I killed Astra, Kara. I mean, I let you think I did. I let you believe your last family in the galaxy was dead and I let J'onn take the blame, and I'm the one who woke you from the Black Mercy. In one day, I took your whole world away." Alex wipes her face, although the tears keep falling. "And I did it because I'm weak. I was terrified of losing you. But you don't need me..."

"Yes I do!" Kara pulls back, takes Alex's face in her hands. Her blue eyes are shining with tears, but they're also full of so much love that Alex can barely breathe. "Alex, I became Supergirl for you. That plane...if you hadn't been on it, I wouldn't have done anything. I would have stayed hidden, stayed safe, because I knew it's what you wanted. But when you were in danger, I had to save you, no matter what it cost. And yeah, I love being Supergirl, but none of it means anything if you're not here with me! I watched my planet die in front of my eyes...everyone I had ever loved...losing you would kill me." Kara takes a shaky breath. "You're my family, my big sister and my best friend, but more than that, you're my strength. Alex...you've always been my superhero. I just wanted to be yours too."

That does it. Alex loses what little composure she still has, tucking her face into Kara's shoulder like she had that day in the training room after confessing to Astra's "murder". She cries and cries, great, heaving sobs making her body shake as she clings to Kara so tightly that the blonde would probably have broken ribs were she human. Kara rocks her, soothing Alex through tears of her own as she whispers promises that Alex herself had made so long ago back when Kara was still a stranger to the planet under a yellow sun.

 _I won't leave you._

 _I'll be your sister forever._

 _I love you._

It's a long, long time before Alex is able to speak again. She's utterly exhausted, drained from the effort of crying, but she has to know—"You're not going to try and...do anything, are you?"

Kara shakes her head. "No. Astra convinced me to stay. I'm...I'm still terrified of going off the rails again, but I know if I left...it wouldn't fix things the way I thought."

"I won't let you go." Alex finds Kara's hand, twines their fingers and squeezes as hard as she can. "I won't ever let go."

"Promise?" Kara whispers, sounding so much younger than her twenty-four years.

"Of course I do. Kara, you're my sister, and I love you. No matter what." Alex smiles slightly. "That doesn't mean I'm not still angry as hell at you."

"I know." The blonde snuggles closer to her big sister. "But that can wait until after we've rewatched _Homeland_ , right?"

"You're such a brat." The words are undermined as Alex presses a kiss to Kara's hair. "But I guess we could both use a good old Netflix marathon after yesterday."

"Hey, Alex?" Kara looks up at her.

"Yeah?"

"I love you." The utter sincerity in those three words hurts in all the best ways. "You know that?"

"I know," Alex finally whispers, her throat tight. "I love you too, Kara."

That's how Astra finds them when she deems it safe to finally check on her two favorite humans: Alex's arms around Kara as Kara curls against her, head resting over her older sister's heart. There's something playing on the screen in front of them—one of those annoying pop culture references Alex finds it hilarious to make around her—but what catches Astra's eye is the light in Alex's and the way Kara shrieks with laughter when Alex makes some stupid joke about one of the characters.

She knew they would be stronger together, that they would go into the fire as iron and come out as steel. It looks like now, so do they.


End file.
